The beer the company has become most famous for—porter stout—was based on a London ale, a favourite of the street porters of Covent Garden and Billingsgate markets. Since 1886 the firm has floated on the London Stock Exchange, and the company moved its headquarters to London in 1932, where it has been based ever since (it merged with Grand Metropolitan and renamed itself Diageo in 1997). Even in terms of branding, the company was considering disassociating itself from its Irish reputation as recently as the 1980s. Worried about the impact on sales of the IRA’s terrorist campaign during the Troubles, Guinness came close in 1982 to re-launching the brand as an English beer brewed in west London. But as Northern Ireland’s situation improved in the 1990s, the company’s marketing strategy changed again towards marketing the beer as Irish, aiming its product at tourists in Ireland and the estimated 70m people of Irish descent living around the world. Now the Guinness Storehouse, part of the original Dublin factory which was reopened as a tourist attraction in 2000, promotes Guinness to tourists as an Irish beer once again.